Pronghorn Reintroduction Update – By Leif Olsen

What began at Auction 2013 has carried forward into the San Diego Chapter taking an important role in the reintroduction of an endangered species. After review of the biological analysis of our local habitats, it was determined that our best path for the reintroduction of pronghorn to Southern California rests with the Sonoran antelope.

The Sonoran pronghorn (Antilocapra Americana sonoriensis), federally listed as an endangered species in 1967, is one of five subspecies endemic to western North America and one of three subspecies adapted to the hostile environmental conditions associated with southwestern deserts. Prior to extensive settlement and associated development throughout the species’ historical range in southern Arizona and northern Mexico, Sonoran pronghorn originally inhabited and ranged widely throughout the Sonoran Desert, but are now confined to an increasingly isolated and fragmented portion of their former range. Specific pressures that affected Sonoran pronghorn populations included unrestricted hunting, livestock grazing, prolonged drought, and habitat fragmentation due to the construction of fences, railroads, highways and canals.

Currently, an estimated 160 and 400 Sonoran pronghorn survive in the wild in southwestern Arizona, United States, and northwestern Sonora, Mexico, respectively, making it among one of the most endangered land mammals in North America. Following severe drought conditions that persisted through 2002, the entire U.S. Sonoran pronghorn population declined to an estimated 21 animals. Had the drought persisted further, it is likely that the remaining U.S. population would have perished.

With this dire situation, a multi-agency task force was established. The Sonoran Pronghorn Recovery Team was created with members including: United States Fish and Wildlife Service, Bureau of Land Management, Arizona Game and Fish, The United States Marine Corps, United States Air Force, Arizona State University, The Arizona Antelope Foundation and many more.

The Recovery Team has created safe breeding habitat and has been extremely successful in establishing a second population of Sonoran pronghorn located on the Barry Goldwater range in Arizona. The Recovery Team is currently reviewing additional sites for potential reintroduction, and this is where our San Diego Chapter is taking a significant role to bring the Sonoran antelope back to California.

Already meetings with local Fish and Wildlife personnel have taken place, and more importantly, the San Diego Chapter is sponsoring DNA analysis from specimens collected from the 1920’s-30’s currently located at the Smithsonian. This analysis not only will provide important insight into the historical range of the antelope in California, but establishes the San Diego Chapter as a major player in the reintroduction of an endangered species.

On June 14, 2013, a multi-agency meeting will be held at the Palm Springs office of the US Fish and Wildlife Service to discuss the necessary steps to bring Sonoran antelope to an area named the Chuckwalla Bench located northeast of the Salton Sea. The Chuckwalla bench has been identified as the best of three possible locations evaluated by Kevin Clark of the San Diego Natural History Museum and David Brown of Arizona State University.

It should be noted that because of the work of Leon Lesicka and Desert Wildlife Unlimited (DWU), the Chuckwalla Bench already has water sources to aid in this important project. As in the past, SDSCI and DWU are collaborating to bring back the Sonoran Pronghorn. I look forward to reporting on the outcome of the June meeting and providing additional updates on this exciting work.